Kyle Wayne Unger, seen here in this undated CBC image, will not be retried for the 1990 Manitoba murder of Brigitte Grenier, 16, a source close to the case said Thursday. (CBC)

Manitoba prosecutors will not proceed with a retrial of a man who spent 14 years in a B.C. prison for the sexual assault and killing of a teenager at a rock concert in a small Manitoba community.

Kyle Unger is expected to walk out of the Manitoba Law Courts building a free man after a hearing in Winnipeg Friday morning, CBC News has learned.

A source close to the case said Crown prosecutors have no new evidence with which to prosecute Unger for the murder of Brigitte Grenier, 16.

Unger was convicted, along with another man, of first-degree murder following the death of Grenier at an outdoor concert near Roseisle in June 1990. Grenier had been beaten, strangled and sexually mutilated.

A new trial for Unger was ordered in March after federal Justice Minister Rob Nicholson ruled there was a reasonable likelihood he had been wrongfully convicted.

"I am satisfied there is a reasonable basis to conclude that a miscarriage of justice likely occurred in Mr. Unger's 1992 conviction," Nicholson said.

Unger has been on bail and living in B.C. since November 2005 when new DNA testing suggested a strand of hair found at the scene of the crime and originally used to convict Unger did not come from him.

Unger's lawyer subsequently filed an application to the minister of justice for a review of the murder conviction.

Unger's co-accused, Timothy Houlahan, was also convicted for the murder. He was released on bail after his conviction was overturned by the Manitoba Court of Appeal in 1994. He committed suicide later that same year.

Although court was told at the time of the trials that Unger and Houlahan did not know one another, the Crown prosecutor argued they conspired to kill Grenier.

The prosecutor was George Dangerfield, who has made news in recent years as a number of his cases have been overturned as wrongful convictions. Those past cases included those of Thomas Sophonow and James Driskell.

The province responded by retaining retired Ontario justice Roger Salhany to review the Dangerfield prosecutions.